There has hitherto been known a vehicle AC power generator configured to generate a cooling air by a cooling fan rotated integrally with a rotor in order to cool coil ends of a plurality of stator coils arranged on a radially outer side of the rotor. In such related-art vehicle AC power generator, the following structure has been proposed in order to improve cooling performance on the coil ends by the cooling air from the cooling fan. That is, the coil ends of adjacent stator coils have different lengths so as to form a step between the coil ends, to thereby increase a contact area of the coil end with the cooling air (see, for example, Patent Literature 1).